1. Field of the Invention
This invention relates to a seat damper and in particular to a seat damper to be employed in a seat supporting mechanism for a small-sized and high-speed boat such as a motor boat or the like.
2. Description of the Prior Art
A hull of a small-sized ship such as a motor boat may receive a repetitive and continuous shock during its high speed running from a striking of the bow against the wave or a severe striking of the bottoms against the water surface. In addition, an intensity of the striking force during this running operation reaches such an extent that an occupant has to get an anti-shock attitude even in case of his seating on the seat.
Due to this fact, there are many seats for the type of ship as described above which are provided with a supporting column structure having a spring type or an oil type damper mechanism or the like.
For example, as its practical means, the prior art supporting column structure is, as disclosed in the specification of U.S. Pat. No. 4,842,238, constructed such that the column structure is composed of a cylindrical lower bracket having a widened bottom part for making a stable installation at an installing bottom surface. An inner tube slidably inserted into the lower bracket, and a damper arranged within the inner tube, wherein the inner tube is operated to move up and down under an action of the damper so as to absorb or damp energies such as striking and vibration or the like applied from the external side to the seat.
According to the configuration of the supporting column structure composed of such a prior art means, an inner diameter part of a receiving cylinder for a lower bracket for directly fitting and sliding the inner tube should be finished to have a high precision and this causes a cost of the system to be increased. Further, employment of this type of supporting column structure in various configurations having different damper strokes requires an arrangement of exclusive lower brackets for each of the machine types in the prior art where the lower bracket acts as the outer tube. Even then such a prior art configuration means did not show any convertibility of the lower bracket between the machine types and this causes additional costs.